1. Field of the Invention
The present invention relates to a device for the turning of flat articles, and particularly to a device for turning folded box blanks.
2. Description of the Related Art
When making folded boxes from blanks in folded box gluing machines, various fold flaps, depending on the shape of the box, provided with a glue strip must be folded by about 180° and glued to other blank parts. Since the folding is performed at high speeds as the blanks are moved through the machine, folding elements arranged at the sides are typically used to fold the fold flaps disposed at the sides of the blanks towards the middle. Thus, the respective groove line of the side flaps extends in a direction substantially parallel to the direction of conveyance.
For certain box shapes, when blank parts need to be folded about two groove lines that are substantially perpendicular to each other, for example, parts forming the top of the box in addition to the side flaps, the blanks are usually conveyed through the machine twice, the blank being turned by about 90° for the second conveyance, such that the parts being folded are disposed along the lengthwise side of the machine for each conveyance.
To enable such boxes to be processed with only one conveyance through the machine, it is known to turn the boxes by about 90° before performing the second folding. EP 0 881 173 B1 describes a device of this type which includes two conveying sections arranged alongside each other along the path of the articles for turning the folded boxes by as much as about 180°, the speeds of which can be separately adjusted. The articles lie on both conveying sections, so that they can be turned about an axis substantially perpendicular to the plane of conveyance when the two conveying sections have different speeds. In order for the articles to be conveyed at the speed of the two conveyors each time, a suction mechanism is arranged underneath the conveying elements which increases the frictional force between the conveying elements and the articles by creating a partial vacuum.
The conveyors are mounted in a frame. The frame can be transversely adjusted with respect to the machine frame in order to orient the box blanks so that they are substantially centered with respect to a center axis of the other processing stations of the folded box gluing machine located downstream.
From EP 1 345 827 B1, a device is known for the turning flat articles in which the conveying elements define only a single conveying section. At one side next to the conveying section, a sliding surface extends substantially flush with the conveying plane in which a brake element is arranged that can be activated by a clock. With the brake element, a portion of the blank sliding over the sliding surface can be braked. Since the other portions of the blank continue their motion, a turning movement is performed.
From EP 1 593 481 A1, a device is known for turning flat articles with an immovably arranged transport component for the blanks and with a control unit, which controls the servo-drives of the machine components provided before and after the turning station and which can be transversely positioned, depending on the type of folded box being produced.